“L-carnitine supplementation induces regression of NASH even if both plasma and hepatic carnitine levels have been shown to be normal,” the investigators report in the January 21 online issue of the American Journal of Gastroenterology.

Overall, 35 of the 36 patients (97%) in the intervention group had a histological response, and the NASH activity score – a 12-point scale assessing steatosis, parenchymal inflammation, and hepatocellular injury – fell by at least 2 points in every patient, according to lead author Dr. Mariano Malaguarnera and associates at the University of Catania.

In their double-blind study, Dr. Malaguarnera and colleagues randomized 74 patients with NASH to either L-carnitine (a 1 g tablet after breakfast and another after dinner) or placebo for 24 weeks. All patients were put on a 1600-calorie/day diet that met requirements of the National Cholesterol Education Program, as well as a whole-body stretching routine performed 3 times a week.

At the end of the study, the NASH activity score improved significantly more in the L- carnitine group (mean decrease 6.23 vs 3.63, p < 0.001). On a scale of 1 to 4, fibrosis also improved significantly more in the L-carnitine group (mean change 1.31 vs 0.85, p < 0.05).

In addition, the L-carnitine group had significantly greater decreases in liver enzymes (aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl-transpeptidase, P < 0.01 for each). Similarly, L-carnitine was associated with greater reductions in total cholesterol and LDL cholesterol (p = 0.000 for both).

Only the L-carnitine group had a significant reduction in mean plasma glucose, and the change in insulin resistance also favored L-carnitine treatment (p = 0.000).

Finally, levels of C-reactive protein and tumor necrosis factor-alpha declined significantly more in the carnitine group (p < 0.005).

L-carnitine was well tolerated, according to the report.

The authors note that before their study, they had theorized that L-carnitine would benefit NASH patients through its interference with oxidation, inflammation and accumulation of the lipotoxic metabolites that cause mitochondrial dysfunction and insulin resistance.

Now, they conclude, “L-carnitine treatment and lifestyle changes, including weight loss and exercise, can represent therapeutic options in NASH.”